Clamping device for printing plates



May 29, 1934. s. w. MARVIN CLAMPING DEVICE FOR PRINTING PLATES PatentedMay 2 9, 1934 UNITED STTES a rcr.

one-third to William J. Marsh, Concord, Mass,

and one-third to Charles G. Wells, Boston,

Mass.

Application September 17, 1932, Serial No. 633,592

4 Claims.

This invention relates to a clamp or gripping device for use with thebed block of a printing press having slots or channels in the uppersurface thereof, and in which slots or channels the clamp or grippingdevice is bodily movable lengthwise of the slot or channel toward andfrom a printing plate on said bed block.

A clamp or gripping device of this character is shown and described inU. S. Patent No. 1,628,384 granted to me May 10, 1927.

The present invention is an improvement upon the clamp or grippingdevice shown in the patent referred to and has for its object to providea clamping device, which is materially simpler, less expensive andequally efficient, and which can be quickly manipulated, whereby theprinting plates on the bed block may be adjusted thereon and securedthereto by the operator in a minimum time.

To this end, the clamping device embodying this invention is providedwith a bar or member insertible into the slot or channel in-the bedblock and slidable lengthwise of said slot or channel, and is furtherprovided with a rotatable member which is carried by said bar'and' isadapted by rotary movement to be engaged with one side wall of the slotand to cause the bar to be engaged with the opposing side wall of theslot so as to secure the clamping device in fixed relation to the bedblock.

The bar or member slidable in the slot is also provided with a catch ormember extended transversely thereof above the same for engaging theprinting plate, and said bar is preferably provided with a second memberextended transversely thereof which co-operates with the catch to form aguideway for a tool by which the rotatable member is rotated.

These and other features of the invention will be pointed out in theclaims at the end of this specification.

Fig. 1 is a plan of a bed block of a printing press with a printingplate secured thereon by clamping devices embodying this invention, oneof the clamping devices being shown by dotted lines out of engagementwith the printing plate;

Fig. 2, a plan on a larger scale of one of the clamping devices shown inFig. 1, and a portion of the bed block;

Fig. 3, a plan of the clamping device shown in Fig. 2 with the rotatableclamping member in its operative position;

Fig. 4, a side elevation of the clamping device shown in Fig. 2 lookingin the direction of the arrow thereon;

Fig. 5, a View like Fig. 4, with the rotatable clamping member removed;

Fig. 6, a detail in plan of the rotatable clamping member shown in Figs.1 and 2;

Figs. 7 and 8, plan view of modifications to be referred to;

Fig. 9, a sectional view tion to be referred to;

Fig. 10, a side elevation of one form of tool for of a further modificaeoperating the clamping device shown in Figs. 1

and 2, and

Fig. 11, an inverted plan of the tool shown in The clamping devices inaccordance with this invention are provided with a bar or member 16,which is insertible into the slot or channel 13 and is slidablelengthwise thereof, and said bar or member 16 is designed to be engagedwith one wall as 14 of the slot 13 and will be hereinafter referred toas the slidable clamping member of the clamping device.

The bar or member 16 carries a rotatable clamping member which isdesigned to be engaged with the opposing wall 15 of the slot 13 and inthe preferred construction shown in Figs. 1 to 6, the rotatable clampingmember is formed by the head 18 of a'screw or shaft 19 in engagementwith a threaded socket or bore 20 in the sliding clamping member 16which bore is located below the upper surface of the sliding clampingmember and is'extended transversely of the latter. The head 18 of thescrew 19 is provided on its circumference with gear teeth 22, some ofwhich project above the upper surface of the sliding clamping bar 16, soas to be capable of engagement by a suitable tool shown in Figs. 10 and11, said tool having a blade 24 provided on its under side with teeth25, which in the present instance are shown as inclined with relation tothe blade. The teeth 25 are designed to be engaged with the teeth 22 ofthe rotatable clamping member, and by movement of the tool transverselyof the slidable clamping member 16 in the direction indicated by thearrow 26 in Fig. 2, the rotatable clamping member is rotated in suchdirection as to move the toothed head 18 out of a socket 28 in one faceof the bar or slidable clamping member 16 after the manner representedin Fig. 3, and by such rotation of the toothed head of the screw, thesaid head is brought into engagement with the wall 15 of the slot 13 andfurther rotation of the toothed head is limited by the wall 15 andeffects movement of the slidable clamping member or bar 16 against thewall 14 with sufiicient force to cause the clamping device to be firmlypressed against the vertical walls of the slot.

Movement of the tool in the direction opposite to that indicated by thearrow 26 in Fig. 2 effects rotation of the rotatable clamping member 18in the opposite direction and effects disengagement of the clampingdevice from the walls of the slot. The operating tool 24 is providedwith a suitable handle 29 (see Fig. 10).

Provision is made for guiding the tool 24 in its movement to effectrotation of the toothed head :18 of the screw 19, and to this end theslidable bar 16 has secured to or forming part thereof two cross membersor bars 30, 31, suitably spaced apart to ensure the engagement of theteeth 25 of the tool with the teeth 22 of the rotatable clamping member18 during the movement of the tool to effect rotation of the rotatableclamping member. The cross bars 30, 31 are preferably pro- Vided ontheir outer sides with inclined surfaces 32 (see Fig. 4) whichco-operate with a bevel or inclined edge 33 of the printing plate andthereby form stationary catches which engage the plate and serve tofirmly clamp the plate onto the bed block.

In the construction shown in Figs. 1 to 6 the toothed rotatable clampingmember 18 is shown as fixed to the screw or threaded shank 19 so as torotate as one piece, the movement of the rotatable clamping memberoutwardly from the block and into engagement with the wall of the slotbeing effected by the rotation of the threaded shank 19 of the screw inthe threaded bore or socket 20 in the bar or slidable member 16..

While this construction may be preferred, it is not desired to limit theinvention in this respect as the toothed rotatable clamping member 18may be mounted to turn on the shank or threaded shaft 19, after themanner represented in Fig. 9, and in this latter case the threaded shafton which the toothed member is rotated may be stationary with relationto the sliding clamping member 16.

.So also it may be preferred to provide the rotatable clamping member 18with teeth 22 on its outer circumference, but it is not desired to limitthe invention in this respect, as the rotatable clamping member 18 maybe provided with an untoothed or smooth circumference having suitablesockets or holes 35 shown in Fig. 7, by which the rotation of theclamping member may be effected by means of a pin or other suitabletool, not shown.

While it may be preferred to have the rotatable clamping member 18normally located within a socket in the slidable clamping member 16 asrepresented in Fig. 2, it is not desired to limit the invention in thisrespect, as the rotatable clamping member may be located outside of thesliding member after the manner represented in Fig. 8.

The operation of the clamping device may be briefly described asfollows:

'The bar or slidable member 16 is inserted into a slot 13 in the bedblock and after the printing plate has been laid upon the bed block, theoperator places the toothed blade 24 in the guideway formed by thestationary catches 30, 31 and engages the teeth 25 of the tool with theteeth 22 of the rotatable clamping member 18. At such time the block orslidable clamping member 16 is free to move lengthwise of the slot inthe bed block and this lengthwise movement is effected by means of thetool 24, the handle 29 of which is grasped by the operator and movedtoward or from the printing plate on the bed block.

By movement of the handle of the operating tool toward or from theprinting plate, one of the catches as for instance the catch 30 isengaged with one edge of the plate 12, and when thus engaged theoperator moves the tool transversely of the slidable clamping member 16in the direction indicated by the arrow 26, Fig. 2, and effects rotationof the rotatable clamping member 18 so as to cause the rotatableclamping member to engage the wall 15 and thereby cause the slidingclamping member 16 to be engaged with the wall 14 of the slot and inthis manner firmly secure the clamping device in fixed relation to thebed block with the stationary catch 30 or 31 in engagement with theprinting plate.

When the clamping device is thus properly positioned, the operatorremoves the tool and performs the same operation on another clampingdevice.

The printing plate is usually clamped on its opposite sides by two ormore clamping members, and the stationary catches 30, 31 of thoseclamping devices which are to co-operate with the sides of the plate arearranged so that the clamping member 31 can be used to engage the plateon the left hand side of the plate, viewing Fig. 1, whereas the clampingmember 30 engages the right hand side of the printing plate.

Clamping devices are also used at the top and bottom and when thus used,the stationary catches 30, 31 are arranged transversely of the slidingmember or bar 16 after the manner represented in Fig. 1 at the top andbottom of the printing plate.

When it is desired to remove the printing plate, or to adjust it on thebed block, the clamping device may be released by engaging the tool 24with the rotatable clamping member 18 and moving the said tool in thedirection opposite to that indicated by the arrow 26, after which theclamping device may be moved in the slot 13 in the bed block away fromthe printing plate, and into a position such as indicated by dottedlines in Fig. 1. The clamping device may then be rendered stationary onthe bed block by moving the tool 24 in the direction indicated by thearrow 26.

From the above description, it will be seen that the clamping device iscomposed of a minimum number of parts, and may be manufactured at aminimum cost. It will also be observed that the clamping device can bequickly and easily operated and when in operative relation to theprinting plate effectively secures the latter to the bed block.

What is claimed is:

1. A clamping device of the character described having, in combination,a slidable clamping member capable of being inserted into a slot in theupper surface of the bed block of a printing press L and of slidinglengthwise of said slot, a rotatable clamping member carried by saidslidable clamping member and adapted to be engaged with one wall of saidslot and effect engagement of the slidable clamping member with theopposing wall of said slot, and cross members secured to said slidableclamping member and extended transversely thereof to form a guidewaythrough which said rotatable clamping member is accessible from abovethe bed block.

2. A clamping device of the character described having, in combination,a bar capable of being inserted into a slot in the upper surface of thebed block of a printing press and of sliding lengthwise of said slot, ashaft carried by said slidable bar and extended transversely thereofbelow the upper surface of said bar, a head on said shaft provided onits circumference with teeth extended above the upper surface of saidbar to be engaged by a tool movable transversely of said bed block, andmeans on said bar for guiding said tool as it is moved transversely ofthe bar to rotate the toothed head in the direction of the length ofsaid slot.

3. A clamping device of the character described having, in combination,a slidable clamping member capable of being inserted into a slot in theupper surface of the bed block of a printing press and of slidinglengthwise of said slot, a shaft carried by said slidable clampingmember and extended transversely of the slidable clamping member belowthe upper surface thereof, a device mounted on said shaft and providedon its circumference with teeth extended above the upper surface of saidslidable clamping member and out of said slot to enable said device tobe rotated in the direction of the length of said slot by a tool movabletransversely of said slot and above said bed block, and means forguiding said tool in said transverse movement.

4. A clamping device of the character described having, in combination,a clamping member slidable lengthwise in a slot in the upper surface ofthe bed block of a printing press and adapted to engage one wall of saidslot, means on said clamping member for forming a guideway for a toolmovable with said clamping member in the direction of the length of theslot and movable in said guideway transversely of the clamping member,and a rotatable toothed device carried by said clamping member andarranged with relation to said guideway to be actuated by movement ofsaid tool transversely of said clamping member to secure the latter infixed relation to said bed block.

SAMUEL W. MARVIN.

